1. Technical Field
The present invention relates to liquid supply systems equipped with liquid supply units that supply liquid to liquid ejection apparatuses.
2. Related Art
Printers are widely used as a kind of liquid ejection apparatuses, and ink cartridges are used as liquid supply units for the printers. Hitherto, with a printer that prints using ink of a plurality of colors, independent ink cartridges are prepared for respective ink colors and are independently attached to and detached from the printer. However, in the case of using independent ink cartridges for the respective ink colors, if the number of ink colors increases, the structure of a cartridge attaching portion becomes complicated as a result of enabling many ink cartridges to be attached, which is disadvantageous for a size reduction of the printer. In addition, the operation of replacing the ink cartridges takes time and effort.
A printer has been proposed to which an integrated ink cartridge that contains ink of a plurality of colors is attached to perform. For example, JP-A-2008-74100 discloses an ink tank (ink cartridge) in which the inside of a housing thereof is partitioned into a plurality of ink containing portions and an ink supply port is provided in each ink containing portion. The ink tank has a plurality of lock portions, and is attached to the printer by engaging these lock portions with lock portions on the printer side.
With an integrated ink cartridge such as the one disclosed in JP-A-2008-74100, time and effort in the operation of replacing the ink cartridge can be reduced since a plurality of ink cartridges are integrated. Furthermore, an integrated ink cartridge is more space-saving than a plurality of ink cartridges are, and allows the configuration of a cartridge attaching portion to be simplified. Accordingly, an integrated ink cartridge is advantageous for a size reduction of a printer.
However, although an integrated ink cartridge is advantageous in terms of a size reduction and time and effort in replacement, an entire ink cartridge needs to be replaced if the remaining amount of ink of only one of the plurality of ink colors becomes small. Accordingly, a problem arises in that the ink is wasted. For this reason, there has been a demand for an ink cartridge that is advantageous for a size reduction and time and effort in replacement and with less waste of ink. This problem is not limited to ink cartridges for printers, but is also a problem shared by liquid supply systems for other kinds of liquid ejection apparatuses.